Mullis, AM, Cao, LG and Cochrane, RF (2014) Non-equilibrium processing of Ni-Si alloys at high undercooling and high cooling rates. Materials Science Forum, 790-79. 22 - 27. ISSN 0255-5476
Abstract
Melt encasement (fluxing) and drop-tube techniques have been used to solidify a Ni-25 at.% Si alloy under conditions of high undercooling and high cooling rates respectively. During undercooling experiments a eutectic structure was observed, comprising alternating lamellae of single phase γ(NiSi) and Ni-rich lamellae containing of a fine (200-400 nm) dispersion of β- NiSi and α-Ni. This is contrary to the equilibrium phase diagram from which direct solidification to β-NiSi would be expected for undercoolings in excess of 53 K. Conversely, during drop-tube experiments a fine (50 nm) lamellar structure comprising alternating lamellae of the metastable phase NiSi and β-NiSi is observed. This is also thought to be the result of primary eutectic solidification. Both observations would be consistent with the formation of the high temperature form of the β-phase (β/β) being suppressed from the melt.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) 2014, Trans Tech Publications. This is an author produced version of a paper published in Materials Science Forum. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Intermetallics; Rapid Solidification; Undercooling |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) > Institute for Materials Research (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 29 Jul 2014 10:07 |
Last Modified: | 16 Jan 2018 10:36 |
Published Version: | http://dx.doi.org/10.4028/www.scientific.net/MSF.7... |
Status: | Published |
Publisher: | Trans Tech Publications |
Identification Number: | 10.4028/www.scientific.net/MSF.790-791.22 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:79861 |